1. Field of the Invention
The present invention relates to a data processing terminal, and more particularly, to a hand-held data processing terminal to be connected to an optional external device.
2. Description of the Related Art
Recently, hand-held data processing terminals have been used to collect data at the point of generation of the data, to order commodities and to manage stocks. The terminals are used in various industries, such as the distribution, manufacturing, power, gas, and water industries, to enable operators to enter and process data at a point of generation of the data that may be outdoors or indoors.
The data collected by the terminals are transferred to a personal computer or a server, which analyzes and processes the data, to make decisions on business plans and customer service.
One of the data input techniques usually adopted by the terminals is to read bar codes. Compared with manually entering data through a keyboard, reading bar codes is simple and fast and involves less errors.
The bar codes are read by a pen scanner, a touch scanner, or a laser scanner connected to the terminal, and bar code data are transferred to the terminal.
By the way, control command systems for bar code readers, including pen scanners, touch scanners, and laser scanners, differ from one another depending on their types. If a control command system in a given hand-held data processing terminal is entirely different from that of the bar code reader connected to the terminal, the bar code reader may not work. Moreover, if the command system in the terminal is connected to the wrong bar code reader, it may damage the bar code reader.
This trouble will not happen if all bar code readers employ the same command system. This, however, is not practical because it costs a large amount of money to remodel bar code readers. It is more economical to use marketed bar code readers. The problems of the related art will be explained in detail later.